Hi,
I'm on Windows 2008, DB 11.2.0.4 and downloaded last Opatch to apply  PS 11.2.0.4.10.
I have the following problem. I saw Opatch Faq and set ORACLE_HOME and verify context/inventory but :
C:\app\administrateur\product\11.2.0\dbhome_1\OPatch>set ORACLE_HOME=C:\app\administrateur\product\11.2.0\dbhome_1
C:\app\administrateur\product\11.2.0\dbhome_1\OPatch>opatch version
Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number in .class file
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
OPatch failed with error code = 1
Here is my context/inventory file :
</VERSION_INFO>
<HOME_LIST>
<HOME NAME="OraDb11g_home1" LOC="C:\app\administrateur\product\11.2.0\dbhome_1" TYPE="O" IDX="1"/>
Thank you.